Avalanche Hazards and Rescue Drills

Remarks SubjectTimesIntroduction2 Mins1.There are number of dangers / hazards experienced by theindividuals operating in the mountains and particularly in snow boundareas. Avalanches are one of the main dangers in these areas. Troopsoperating in these areas must be taught avalanche hazards and

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thoroughly trained in rescue drills.

Aim1 Min2.The aim of this lecture is to teach you about avalanche hazardsand rescue drillsAvalanche2 Mins3.The danger of avalanches must be carefully considered whenlarge body move are being conducted in mountains. Avalanches occurwhen the weight and pressure of the snow over-comes the power ofresistance and friction of the under layer. Or the tension in the snowcover is disturbed.Basic Causes of Avalanches3 Mins4. There are two main causes of formation of an avalanche namelyterrain and climate:a. Terrain.Smooth even slopes of bare earth and solid rocksfavors formation of avalanche. The most common altitude foravalanche is between about, 2,000 M to 3000 M. Above 3000M avalanches are comparatively rare because slopes aregenerally steeper which do not let the snow accumulate andwinds are very strong which disperse the snow quickly. Gulliesmake available slide paths for avalanches. The convex slopesare likely to avalanche formation is Slide the grade of the slope.Higher the slope angle more likely it is to slide regardless ofany other condition. The minimum angle favorable to avalancheRESTIRICTED

2RESTIRICTEDis a slope of 22o. Critical avalanche zones are sheer slopes ofabove 25o angles, moreover faces which are exposed to sunfavors avalanches, leeward slope can be likely place ofb.

avalanche.Climate and Weather.

In addition to the terrain factors, 3 Mins

climate and weather are the other basic causes for theavalanches. High rate of snowfall and storms which deposit upto 3 feet of new snow in one continues down pour can formavalanches. Fluctuation in temperature and rainfall can melt thelower layers, there by loosening the grip of snow over theslopes. When its windy, snow is often drifted from one toanother place. Thereby over loading the slopes to the extent ofShowSlide

creating on avalanche.5. Additional Causes of Avalanchesa.

Over Loading.

Weight is probably the most frequent

cause of avalanche. New snow piles up until the cohesion

between the mass of the snow and surface of the slope is lostand the snow structure collapse of its own weight and begins tob.

slide.Shearing.

This can happen in various ways i.e. the sliding

action of a pair of skies, award of snow falling out of trees or

cliff footsteps or even whistling can cause an avalanche onc.

critical slopes.Temperature.

Temperature causes avalanches more than

any other factor except weight and overloading. Rises in

temperature weaken the bonds while a fall in temp retardsd.

settlement of the snow in contact with the slope.

Vibration. This factor is closely related with shearing. It istreated separately because it triggers avalanche from longdistance. Avalanche may be released because of thunders,earthquakes, speeding aircraft explosive etc. Avalanches havebeen occurred because of nuclear detonation as far as 20miles.RESTIRICTED

8 Mins

3RESTIRICTEDPrecautions Against Avalanches6. If already familiarized with a few rules, safety against avalanchescan be ensured to a great extent. These are rules of common senseby nature and can reduce the danger of getting caught inavalanches:a. Adjusting of Equipment. When

negotiating

avalanche

threatened area the straps of ice axe and equipment should be

loosened or removed. It will ensure quick removal of all suchb.

equipment, which can get entangled in a snow slide.

Selection of Routes.One must know the avalanchepaths. Avoid moving along bottom of a V shaped valley where

c.

double avalanches can descend from both sides of the slopes.

Weather.Obtain latest weather forecast from best availablesource prior to move. During move remain alert for changing of

d.

weather.Ascend & Descend.

When

avalanche

slopes

are

unavoidable the top of protruding rocks ridges and slopes

e.

should be used for mobility.

Observation and Testing.Area

to

be

traversed,

must

constantly observed for any danger. If situation allows fire a few

f.

rounds before crossing dangerous area.

Proper Timing.Movement must be carried out at propertimings. Early morning hours are the safest. Immediately beforeor after a snowstorm are the most dangerous times for crossing

g.

avalanche threatened areas.

Proper Distance. When crossing an avalanche area moreand more distance be kept between individuals. Minimumnumber of persons should remain for minimum time in anavalanche area. The leading man can be tied with a rope,which should be stretched along the party. Visual contact must

h.

be maintained at all times.

Use of Ropes.On reconnaissance

mission

or

while

testing an avalanche area, one end of brightly colored rope is

tied around the body and trailed behind the individual in thelead. The minimum recommended length of the rope should beRESTIRICTED

16 Mins

4RESTIRICTED60-70 feet.Action When Caught in Avalanche8 Mins7. When caught in avalanche remember most important preceptDONT, PANIC. One must maintain self-control and attempt to stayon the surface trying to get out of the path of the slide executeswimming motions grab at any thing, which can support you. Takeoff the equipment as quick as possible. If completely covered bysnow slide, keep the hands in front of the face using the snow awayfrom face in order to provide space for breathing after being buriedunder snow.Avalanche Rescue8. If an individual is caught in an avalanche prompt and organizedrescue operation offers the only hope for getting the victim alive.Records are, when a person was recovered alive after remainingburied for hours, under the snow. Ordinarily the victim is instantlykilled by crushing or dies from exposure to cold, shock ofsuffocation. An average man can dies from exposure to cold, shockof suffocation. An average man can live for 2 hours, without gettingsuffocated. However, later victims face suffocating him to death.Under any circumstance the rescue and search operation must notbe discontinued for minimum 24 hours.Phases of Rescue Operation16 Mins9. There are generally three phases of rescue operation:(1) The already detailed party is alerted. AT, MT and specialequipment is arranged.(2) Informer or eye witness, if available & knows exact location ofaccident. The eyewitness MUST return to the scene ofaccident with the rescue party even if in poor physical situation.(3) The first party is dispatched under command of an officer orJCO available. This party must not be less than a section. Thisparty must leave within 15 minutes after receiving firstinformation.(4) Party commander posts a sentry near the avalanche forprotection against any other avalanche.RESTIRICTED

5RESTIRICTED(5)

The Last seen point is located and marked. Down hill search

is carried out for the victim.

(6) If any indication of the victim is found, probing immediatelycommences. If no indication is found probing s carried in likelyplaces such as obstruction in the slide path; trees, boulders,cavity etc. The tip and edges of slides are also searched.(7) If the victims are found first aid and artificial respiration is given.b. Follow Up16 Mins(1) Following the first party a second party should be sent with-inone hour. This party carries probes, shovels, sleds, WS, rationetc with them.(2) The unit commander informs the next higher command of theaccident.(3) If the first party is unsuccessful, the follow up party beginssystematic probing of the slides, beginning at the tip andsearching up wards to the last seen point probes are spacedshoulder to shoulder and probe every square foot of the slide.Probes must be pushed in snow very carefully to avoid anyinjury to victim. If the last seen point is known, a special groupmay be assigned to probe area around it.(4) The first party may be relieved by the reinforcement ifnecessary.(5) Shovel crews are organized to assist the carrying out carefuldigging of likely places.(6) Systematic but through search should not take more than 3 to 4hours.(7) If trenches have to be dug in deep snow then the operationshould cease to be of an emergency type.